I'm from Russia and like a huge amount of people, if not dominant, still prefer to use XP or Windows 7 32-bit (XP is second most popular OS after Win 7 64), including me.

I'm curious, could it be that new GZDoom builds are very messy and sprites, textures and what not just dissapearing\vanishing and jumping all over the place in random pattern is not because of buggy GZDoom builds, but because it doesn't support 32 bit OSes anymore?? Unfortunatelly, even recent official GZDoom (not beta build) that was released not so long ago still have the above mentioned issue.

If it's the case that it doesn't support 32 bit OSes anymore, could GZDoom builds get support for 32 bit OSes in future?? If not, that would be extremely sad for me and probably the end for new singleplayer DOOM mod experience for me and many of my russian friends...

32-bit support is still there, hence the dual distribution of both 32- and 64-bit builds. What you're having could be related to your graphics card. Maybe it is or its drivers are outdated. Post your computer's specs. Hopefully, one of the GZDoom developers can give you a clue what the actual cause might be based on that information.

... and let me stress one thing here: When AMD deprecates this old hardware and leaves users stuck with broken drivers, these cards essentially become obsolete. They cause such a shitload of problems now that sooner or later support for them may have to be dropped entirely.

Note that there's no such issue with NVidia hardware of the same generation - it still works fine because the drivers weren't buggy to begin with.

Regarding 32 bit OSs: Make no mistake: These are on their way out. Expect driver support to get progressively worse with increasingly more software developing problems and things not running anymore. I cannot say how long it will take but attrition will make support here increasingly more problematic as well as time goes on - not on GZDoom's side but mainly the drivers and OSs.

32-bit support is still there, hence the dual distribution of both 32- and 64-bit builds. What you're having could be related to your graphics card. Maybe it is or its drivers are outdated. Post your computer's specs. Hopefully, one of the GZDoom developers can give you a clue what the actual cause might be based on that information.

Intel(R) Xeon(R) CPU X5460 @ 3.16GHz (4 CPUs)

3326MB RAM

DirectX 9.0c (4.09.0000.0904)

Well, I have AMD Radeon HD 6670 on XP, could it be the case??

EDIT: Last working GZDoom that was pretty much close to perfect in it's processing was gzdoom-g1.10pre-1359-g6a8e60c
It work without the above mentioned issue and it was released not so long ago. What has changed since then?

EDIT: Last working GZDoom that was pretty much close to perfect in it's processing was gzdoom-g1.10pre-1359-g6a8e60c
It work without the above mentioned issue and it was released not so long ago. What has changed since then?

Well - other than the GL renderer being refactored and completely rewritten from the ground-up, not much.

Spoiler: Zen Sarcasm

1. Do not walk behind me, for I may not lead. Do not walk ahead of me, for I may not follow. Do not walk beside me, either. Just pretty much leave me the hell alone.
2. The journey of a thousand miles begins with a broken fan belt and a leaky tire.
3. It's always darkest before dawn. So if you're going to steal your neighbor's newspaper, that's the time to do it.
4. Don't be irreplaceable. If you can't be replaced, you can't be promoted.
5. No one is listening until you fart.
6. Always remember that you're unique. Just like everyone else.
7. Never test the depth of the water with both feet.
8. If you think nobody cares if you're alive, try missing a couple of car payments.
9. Before you criticize someone, you should walk a mile in their shoes.That way, when you criticize them, you're a mile away and you have their shoes.
10. If at first you don't succeed, skydiving is not for you.
11. Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat and drink beer all day.
12. If you lend someone $20 and never see that person again, it was probably worth it.
13. If you tell the truth, you don't have to remember anything.
14. Sex is like air. It's not important unless you aren't getting any.
15. Don't squat with your spurs on.
16. Some days you're the bug; some days you're the windshield.
17. Don't worry; it only seems kinky the first time.
18. Good judgment comes from bad experience, and a lot of that comes from bad judgment.
19. The quickest way to double your money is to fold it in half and put it back in your pocket.
20. A closed mouth gathers no foot.
21. Duct tape is like the Force. It has a light side and a dark side, and it holds the universe together.
22. There are two theories to arguing with women. Neither one works.
23. Generally speaking, you aren't learning much when your lips are moving.
24. Experience is something you don't get until just after you need it.
25. Never miss a good chance to shut up.
26. We are born naked, wet and hungry, and get slapped on our behind. Then things get worse.
27. Never, under any circumstances, take a sleeping pill and a laxative on the same night.
28. There is a fine line between "hobby" and "mental illness."
29. No matter what happens, somebody will find a way to take it too seriously.
30. There comes a time when you should stop expecting other people to make a big deal about your birthday...around age 12.
31. Everyone seems normal until you get to know them

The main issue here is clearly Windows XP. Being unsupported means that there's basically no chance to ever get updated video drivers for it. And there have been many indications that AMD's last XP drivers were not the best.

In particular they suffer from extremely poor OpenGL core profile support. But Core profile is needed to get continued support on non-Windows platforms, as on Macs there is no modern OpenGL without core profile and on Linux AMD is transitioning to a different driver that also does no longer support compatibility profiles.

I'm sorry to say this but with this system you cannot expect that actively developed software will continue to work indefinitely. This will only get worse in the future.

The main issue here is clearly Windows XP. Being unsupported means that there's basically no chance to ever get updated video drivers for it. And there have been many indications that AMD's last XP drivers were not the best.

In particular they suffer from extremely poor OpenGL core profile support. But Core profile is needed to get continued support on non-Windows platforms, as on Macs there is no modern OpenGL without core profile and on Linux AMD is transitioning to a different driver that also does no longer support compatibility profiles.

I'm sorry to say this but with this system you cannot expect that actively developed software will continue to work indefinitely. This will only get worse in the future.

Regardless that XP is does not supported by Microsoft directly anymore, the AMD (and many other softwares for hardwares) still making updates for XP, maybe it's Russia exclusive considering that XP is still second most popular\used OS around all computers around here. I have no problems with many other games, same Crysis just run without lags and even new titles like Rising Storm work just fine. Besides, the previous version of GZDoom work just perfect.

What exactly has changed, and any chance this issue will be fixed for future GZDooms???

Like it or not, End of Support pretty much means "abandon ship!" for XP. Hardware vendors won't support it, software vendors will stop supporting it soon (including GZDoom), you're basically running an operating system that's literally for 3 years BEGGING to be hacked and randomwared. This is no joke - XP is dead. Period. There's nothing that you can do or say that will change that. Any further updates that ever happen to it are a courtesy. Anyone who cares about their computer would have at least upgraded to 7 by now.

XP was abandoned because there is better software out there. Microsoft knows this. They've tried, obviously unsuccessfully with you, for YEARS, to get you to upgrade, before they left it. It's not their problem, it's not our problem, that you refuse to go forward. It's all on you - and like it or not, soon you will be wishing you did upgrade.

This is a moot argument now. I'm sorry it's not the way you want it to be - but that is the way it is.

Spoiler: Zen Sarcasm

1. Do not walk behind me, for I may not lead. Do not walk ahead of me, for I may not follow. Do not walk beside me, either. Just pretty much leave me the hell alone.
2. The journey of a thousand miles begins with a broken fan belt and a leaky tire.
3. It's always darkest before dawn. So if you're going to steal your neighbor's newspaper, that's the time to do it.
4. Don't be irreplaceable. If you can't be replaced, you can't be promoted.
5. No one is listening until you fart.
6. Always remember that you're unique. Just like everyone else.
7. Never test the depth of the water with both feet.
8. If you think nobody cares if you're alive, try missing a couple of car payments.
9. Before you criticize someone, you should walk a mile in their shoes.That way, when you criticize them, you're a mile away and you have their shoes.
10. If at first you don't succeed, skydiving is not for you.
11. Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat and drink beer all day.
12. If you lend someone $20 and never see that person again, it was probably worth it.
13. If you tell the truth, you don't have to remember anything.
14. Sex is like air. It's not important unless you aren't getting any.
15. Don't squat with your spurs on.
16. Some days you're the bug; some days you're the windshield.
17. Don't worry; it only seems kinky the first time.
18. Good judgment comes from bad experience, and a lot of that comes from bad judgment.
19. The quickest way to double your money is to fold it in half and put it back in your pocket.
20. A closed mouth gathers no foot.
21. Duct tape is like the Force. It has a light side and a dark side, and it holds the universe together.
22. There are two theories to arguing with women. Neither one works.
23. Generally speaking, you aren't learning much when your lips are moving.
24. Experience is something you don't get until just after you need it.
25. Never miss a good chance to shut up.
26. We are born naked, wet and hungry, and get slapped on our behind. Then things get worse.
27. Never, under any circumstances, take a sleeping pill and a laxative on the same night.
28. There is a fine line between "hobby" and "mental illness."
29. No matter what happens, somebody will find a way to take it too seriously.
30. There comes a time when you should stop expecting other people to make a big deal about your birthday...around age 12.
31. Everyone seems normal until you get to know them

EDIT: Last working GZDoom that was pretty much close to perfect in it's processing was gzdoom-g1.10pre-1359-g6a8e60c

What changed since then?
Well, essentially the entire renderer was redone. By that I mean, it now uses a completely different method to send data to the hardware.
Which by itself isn't a problem - but you have to know that AMD has been notorious for quick deprecation of their hardware. In your case this got compounded by also running on a deprecated operationg system, which gave AMD even more incentive to stop driver support even before the hardware itself got deprecated.
This all sums up to the fact that the last XP-compatible driver for your hardware is quite a bit broken when trying to run modern OpenGL software.

The only way to 'fix' this would be to reinstate the old renderer from GZDoom 1.10. Which won't happen because the only systems that would benefit from it are XP systems with deprecated AMD and ATI graphics cards, most notably the Radeon HD 4000-6000 range. It'd be a disservice to everybody running an up-to-date computer.
Also note that these problems do not happen on Intel graphics hardware, they do not happen on NVidia graphics hardware, they do not happen with modern AMD hardware and they even do not happen on older AMD graphics hardware with a modern OS. They only happen with the range of Catalyst drivers that were produced around the time XP support was shut down. These drivers have long been updated for all affected hardware - just not on XP.

Also confirming Rachael that in terms of GZDoom development, XP is considered unsupported. If it still works, nice for you, if not, you are out of luck. We won't deliberately remove support but we also won't do anything to investigate platform specific problems. The OS is no longer being updated and people should stop using it. You are strongly encouraged to upgrade to a still supported Windows version. Once the problem reports become too much or something else is not compatible it will be shut down for good with no attempt being made to keep it alive.